Using DuckDuckGo in Chrome is like asking for privacy while walking around naked in Times Square. Chrome has 100% unrestricted access to anything your user can access on your PC, no matter what search engine you choose.
Here's a full list of what data is sent back to google:
http://lifehacker.com/5763452/what-data-does-chrome-send-to-...Do the autocomplete results still go to google? If so, then enabling DDG on chrome is indeed fruitless.
Just as an FYI, new versions of chrome also sends back the full URL and the hash of any file you download or save. I bumped across this when I was trying to download light table and it din't let me open it. After a bit of research I found file scanning to be the new addition to chrome's malware checks. With all the NSA debacle going on now, I am feeling even more paranoid. I love chrome but I will be switching to Firefox or IE10 soon.